Method of manufaturing a digital magneto-optical signal write/read head

ABSTRACT

A method of manufacturing a digital magneto-optical signal write/read head ( 1 ) including a thin-film in-plane magnetic coil ( 3 ) disposed on an outwardly directed surface ( 5 A) of a coil substrate ( 7 ). Coil lead in and coil lead out sections ( 11,15 ) of the coil ( 3 ) are extended to an interconnection part ( 9 A) of the side surface ( 9 ) of the coil substrate ( 7 ) and first and second spaced interconnecting conductors ( 21,23 ) are deposited on the side surface ( 9 ) of the coil substrate ( 7 ) in electrical connection with the lead in and lead out sections ( 11,15 ) of the magnetic coil ( 3 ) for contacting the external lead in and lead out lines ( 25,29 ). Alternatively first and second contacting conductors ( 29,31 ) may additionally be deposited on a top surface ( 5 B) of the coil substrate ( 7 ) in electrical connection with the first and second interconnecting conductors ( 21,23 ) on the side surface ( 9 A) of the coil substrate ( 7 ) for contacting the said external lead in and lead out lines ( 25,27 ).

The invention relates to a method of manufacturing a magneto-opticalwrite/read head of the type defined in the preamble of independentclaims 1 and 2 and to a write/read head of the type defined in thepreamble of independent claims 8 and 9.

A method and a write/read head of the above type are known fromReference [1] which is herewith incorporated into the presentspecification by reference. Further details relating to magneto-opticalheads of the kind referred to above may be found in references [2] and[3] which herewith are also both incorporated into the presentspecification by incorporation and which were not yet published at thepriority date of the present application.

The magneto-optical write/read head described in reference [1] comprisesa sliding head with integrated focussing lens and magnetic fieldmodulating coil which has been designed and manufactured by the authorsof the reference. The sliding head is intended for use with high datarate, first surface magneto-optical recording. A coil is integrated intothe air bearing surface of the slider to maintain a head-disk distanceof around 1 micron.

A dual layer coil is described made in a thin film process on a glasscoil substrate by growing galvanic Cu between photoresist walls.Insulation between the two coil layers is achieved by a thin oxidelayer. Because in this embodiment the completed coil faces the rotatingdisk, the coil is also covered with a few microns of oxide in order toprotect it from damage by incidental mechanical contact with the disk.

A problem in the manufacture of write/read heads of this kind orwrite/read heads as defined in the preambles of independent claims 1 and2, is the provision of means for contacting the thin film magnetic coilby electrically connecting the coil lead in and lead out sections toexternal lead in and lead out lines which are needed for connecting thecoil to the external electronic circuitry needed for sending signals toand receiving signals from the coil. The coil is located on theoutwardly directed surface of the coil substrate while the lead in andthe lead out lines need to be connected at the opposite side of the coilsubstrate to terminals spaced from the coil substrate. The very smallair gap present between a thin film in-plane magnetic coil of this kindand a rotating magneto-optical disc is too small (in the order of 1micron) to accommodate the external lead in and lead out lines.

It is an object of the invention to provide a method of the kinddescribed which overcomes the above indicated problems, is excellentlysuitable for the manufacture of digital magneto-optical signalwrite/read heads and does not require cumbersome manufacturing stepssuch as making deep via holes through the coil substrate and ischaracterized by the characterizing parts of independent claims 1 and 2respectively.

Extending the coil lead in and lead out sections of the magnetic coil onthe outwardly directed surface of the coil substrate to aninterconnection part of the side surface of the coil substrate caneasily be effected concurrently with the deposition of the coil itselfon the coil substrate. For the deposition of the interconnectingconductors on the side surface of the coil substrate and contactingconductors on the top surface of the coil substrate depositiontechniques may be used which are well known in the art of replicationtechniques and do not require the making of via holes through thesubstrate. In this way digital magneto-optical signal write/read headsmay be produced at low cost which are suitable for use withmagneto-optical discs and which demonstrate a very small head-discdistance while the magnetic coil may be brought into contact with theexternal lead in and lead out lines by suitable contacting means such asbonding, welding or soldering at the lead in and lead out sectionsrespectively provided on the side surface of the coil substrate or withfirst and second contacting conductors respectively on the top surfaceof the coil substrate.

Preferred embodiments of the methods according to independent claims 1and 2 respectively are defined in depending claim 3 and depending claim4 respectively. These preferred embodiments involve the use of anauxiliary substrate to facilitate the handling of the delicatewrite/read heads of the invention and to facilitate the deposition ofconducting material on the coil substrate in such a way that theinterconnecting conductors on the side surface of the coil substrate aredeposited such as to be in electrical contact with the coil lead in andlead out sections of the magnetic coil.

According to claim 5 the coil substrate may be detachably arranged onthe supporting surface of the auxiliary substrate by adhesive meansprovided between the outwardly directed surface of the coil substrateand the supporting surface of the auxiliary substrate.

An advantageous embodiment of the latter method according to theinvention in which an auxiliary substrate is used is defined in claim 6.This embodiment is important in view of the ease of handling a number ofwrite/read heads simultaneously during the steps of providing a maskover a part of the coil substrate and depositing conducting material onthe coil substrate.

A highly interesting embodiment of the invention for use in a method ofmanufacturing a digital magneto-optical signal write/read head accordingto the invention provided with first and second contacting conductors onthe top surface of the coil substrate is defined in claim 7. In this wayan optical lens part of an optical pick-up may be provided on the topsurface of the coil substrate between the lead in and lead outconductors of the coil while any light focussed through the lens maypass through the coil substrate unobstructed by the lead in and lead outconductors. This embodiment provides extended freedom of design comparedto the write/read head known from reference [1] in that the said opticallens part may be located eccentrically in relation to the central axisof the electromagnetic coil.

Independent claims 8 and 9 and claim 10 relate to digitalmagneto-optical write/read heads according to the invention, preferablymanufactured by the method according to the invention.

The invention will now be described in more detail by way ofnon-limiting examples with reference to the drawings in which:

FIG. 1 is a schematic cross sectional view of a sliding disc digitalmagneto-optical signal write/read head according to the inventionco-operating with an optical disc;

FIG. 2 is a plan view of the outwardly directed surface of the coilsubstrate of the write/read head of FIG. 1;

FIG. 3 is an elevational view along the arrow P in FIG. 2 of theinterconnecting part of the side surface of the substrate of FIG. 2;

FIG. 4 is a plan view of the top surface of the coil substrate of FIG.2;

FIG. 5 is a side elevational view along the arrow Q in FIG. 3 of thecoil substrate of FIG. 2;

FIG. 6 is an elevational view similar to the elevational view of FIG. 4but with a different position of a lens part of an optical pick-up;

FIG. 7 is a partial perspective view of an auxiliary substrate stripwith a number of coil substrates arranged on a supporting surface duringa manufacturing step of the digital magneto-optical signal write/readhead according to the invention;

FIG. 8 is a partial perspective view according to FIG. 8 showing theposition of a mask provided over the auxiliary substrate and a pluralityof coil substrates during a further manufacturing step; and

FIG. 9 is a partial perspective view similar to FIGS. 7 and 8 in whichthe mask has been removed and metal interconnecting conductors andcontacting conductors have been deposited on the coil substrates.

The figures in the drawing have been drawn to an arbitrary scale whilecertain dimensions have been exaggerated for the purposes ofillustration. The same reference numbers have been used in the figuresto designate the same or similar parts in the different figures.

FIG. 1 schematically shows a digital magneto-optical signal write/readhead 1 according to the invention. In the embodiment shown in FIG. 1 themagneto-optical signal write/read head 1 comprises an optical lens part45 having a central axis 47. The lens part 45 may be moved up and downalong the central axis 47, as symbolized by the double pointed arrow 49,by a focussing actuator (not shown in the drawing) used for focussing alaser beam 51 emitted from a suitable laser source. Focussing actuatorssuitable for this purpose are well-known by the person skilled in theart of optical and magneto-optical recording so that the focussingactuator, not forming part of the invention itself, will not bedescribed in detail.

The magneto-optical signal write/read head 1 further comprises a coilsubstrate 7, having substantially parallel main surfaces 5A, 5Binterconnected by a joining side surface 9. In the embodiment shown inFIG. 1 the coil substrate 7 is a light transparent slider of the kinddescribed in reference [1] in combination with a magneto-optical disc 53provided with a suitable magneto-optical storage layer 55. The coilsubstrate 7 is separated from the magneto-optical storage layer 55 by anair gap 57 which is dynamically generated by rotation of themagneto-optical disc 53 in the direction of the arrow 59, such thatduring operation a head-disc distance in the gap 57 is maintained of theorder of 1 micron.

A thin film magnetic coil 3 is deposited on the outwardly directedsurface 5A of the coil substrate 7, comprising a continuous electricalconductor pattern with a coil lead in section 11, a coil winding section13 and a coil lead out section 15 (see also FIG. 2). Information aboutthe method of manufacturing the thin film magnetic coil 3 and the leadin and lead out sections 11 and 15 may be found in reference [2] andwill not be described here. The dimensions of the coil 3 are drawn toarbitrary scale. As shown in FIG. 1 the coil may consist of two layerson top of each other. The coil substrate 7 provided with the coil 3 inthe embodiment shown in the FIGS. 1 to 5 and also in the embodimentshown in FIG. 6 is made of glass and is transparent to the laser beam51. On the top surface 5B of the coil substrate 7 a second lens part 61of the optical signal write/read head has been provided, the centralaxis of which substantially coincides with the central axis 47 of thelens part 45. The two lens parts 45 and 61 co-operate to focus the laserbeam 51 into a focussing spot 63 on the surface of the magneto-opticalstorage layer 55 of the magneto-optical storage disc 53.

The whole digital magneto-optical signal write/read head 1 is suspendedin a suitable unit that is very similar to a rotating or translatingoptical pick-up unit known from the prior art, provided with suitablesuspension means for suspending the floating coil substrate 7 such asknown per se for example from magnetic hard disc drive technology.Alternatively the coil substrate 7 could have a configuration differentfrom that of a slider, for example for use with a stationary or slowlymoving magneto-optical storage element instead of the magneto-opticalstorage disc 53. With such an embodiment no air film in the air gap 57can be maintained and the coil substrate 7 could be actuated to move inthe direction symbolized by the double pointed arrow 49 along thecentral axis 47 by a suitable actuator, for example an electromagneticactuator of the kind well known from the prior art of electromagneticactuators for optical and magneto-optical disc drives.

In the embodiment shown in FIG. 1 the laser beam 51 is focussed througha transparent coil substrate 7 through the centre of the coil 3.Alternatively the coil substrate 7 could be opaque and provided with acentral opening at the centre of the thin film coil 3 for lettingthrough the laser beam 51.

A description will now be given of the means for contacting the thinfilm magnetic coil 3 by electrically connecting the coil lead in andlead out sections 11, 15 to external lead in and lead out lines 25, 27to and from the coil.

The coil lead in and lead out sections 11, 15 of the magnetic coil 3 onthe outwardly directed surface 5A have been extended to aninterconnection part 9A of the side surface 9 of the coil substrate 7. Apattern of respective first and second interconnecting conductors 21 and23 has been provided by deposition on the interconnection part 9A of theside surface 9 of the coil substrate 7, in such a way that an electricalconnection is provided to the lead in and lead out sections 11, 15respectively of the magnetic coil 3. In the embodiment of the inventionshown in FIGS. 1, 2 and 3, these interconnecting conductors have beenused for contacting the external lead in and lead out lines 25, 27respectively by suitable contacting means such as bonding, welding orsoldering. In this way a lead in conductor is formed on the coilsubstrate 7 comprising the first interconnecting conductor 21 and thelead in section 11 respectively of the magnetic coil 3 and a lead outconductor is formed comprising the second interconnecting conductor 23and the lead out section 15 respectively of the magnetic coil.

In the embodiment according to FIGS. 4 and 5 an additional pattern ofrespective spaced first and second contacting conductors 29, 31 isprovided on a contacting part 5C of the top surface 5B of the coilsubstrate 7 in electrical connection with the first and secondinterconnecting conductors 23, 24 respectively on the side surface 9 ofthe coil substrate 7 for contacting the said external lead in and leadout lines 25, 27 respectively by suitable contacting means such asbonding, welding or soldering. In this way a lead in conductor is formedcomprising the first contacting conductor 29, the first interconnectingconductor 21 and the lead in section 11 respectively of the magneticcoil and a lead conductor is formed comprising the second contactingconductor 31, the second interconnecting conductor 23 and lead outsection 15 respectively of the magnetic coil 3. With the embodiments ofFIGS. 4 and 5 the lead in and lead out conductors 25, 27 respectivelymay be connected from the top instead of from the side as in FIGS. 1, 2and 3. This may have advantages in certain embodiments.

FIG. 6 is a plan view of a sliding disc digital single write/read head,very similar to the one shown in FIG. 4, comprising a light transparentcoil substrate 7. An optical lens part 41 is provided on the top surface5B of the coil substrate 7 in a position between the lead in and leadout conductors 29, 21, 11 and 31, 23, 15 respectively in a substantiallyeccentric position relative to the centre of the thin film magnetic coil3. The lens part 41 has been positioned such and the lead in and leadout conductors 29, 21, 11 and 31, 23, 15 respectively have been providedon the coil substrate 7 such that any light focussed through the lenspart 41 passes through the coil substrate unobstructed by the lead inand lead out conductors 29, 21, 11 and 31, 23, 15 respectively.

The method of manufacturing the digital magneto-optical signalwrite/read head and more particularly the manufacture of the lead in andlead out conductors on the coil substrate thereof will now be describedin more detail with reference more particularly to FIGS. 7, 8 and 9 ofthe drawings.

An auxiliary substrate 33, which in FIGS. 7, 8 and 9 is formed as astrip shaped auxiliary substrate, is provided having a supportingsurface 35 and a joining auxiliary side surface 37. After depositing thethin film magnetic coil 3 on the outwardly directed surface 5A of thecoil substrate 7 but prior to the steps of depositing theinterconnecting conductors 21, 23 on the interconnection part 9A of theside surface of the coil substrate 7, the coil substrate 7 is detachablyarranged on the supporting surface 35 of the auxiliary substrate 23, ina position in which the thin film magnetic coil 3 is directed to thesupporting surface 35 and the interconnection part 9A of the sidesurface 9 of the coil substrate 7 is flush with the auxiliary sidesurface 37 of the auxiliary substrate 33. The coil substrate 7 may forexample be detachably arranged on the supporting surface 35 of theauxiliary substrate 33 by a thin layer of removable adhesive means (notshown) disposed between the outwardly directed surface 5A of the coilsubstrate 7 and the supporting surface 35 of the auxiliary substrate 33.

Subsequently, see FIG. 8, a mask 39 is provided over a part of theinterconnection part 9A of the side surface 9 and the adjoining part ofthe side surface 37 of the auxiliary substrate 33, such that the areasfor disposing the interconnecting conductors 21, 23 remain exposedareas. In the embodiment of the method shown in FIGS. 8 and 9 the mask39 is not only provided over a part of the interconnection part 9A ofthe side surface 9 but also over a part of the top surface 5B of thecoil substrate 7 so that the areas for disposing the interconnectingconductors 31 and 23 as well as the areas for disposing the contactingconductors 29, 31 remain exposed areas. The embodiment shown in FIGS. 8and 9 therefore is suitable for an embodiment of the coil substrate 7 inaccordance with FIGS. 4 and 5.

The provision of the mask 39 may be effected by means of a manufacturingstep well known in the prior art for providing conducting areas orstripes on substrates and will therefore not be described in detail. Thematerial used for providing the mask 39 may also be entirelyconventional and could consist of for example a suitable photoresist.

As a further manufacturing step a layer of conducting material isdeposited over at least a part of the mask 39 and over the said exposedareas. Suitable processes for depositing a layer of conductive materialare known from the prior art, such as galvanic processes or sputteringprocesses. Subsequently the mask 39 and any conducting materialdeposited thereon is removed (see FIG. 9) so that the pattern of spacedinterconnecting conductors 21, 23 and contacting conductors 29, 31remains on the interconnecting part 9A of the side surface 9 and thecontacting part 5C of the top surface 5B respectively of the coilsubstrate 7.

As a last step the individual coil substrates 7 are removed from theauxiliary substrates 31, for example by melting or dissolving anadhesive layer provided between the detachably connected surfaces of theauxiliary substrate 33 and the individual coil substrates 7.

The individual coil substrates may have very small dimensions, forexample length and width dimensions of the order of one or a fewmillimetres and a thickness of the order of 0.6 millimetres. Componentshaving such small dimensions which need to be provided with thin filmcoils and deposited electrical conductors may be manufactured usingmanufacturing technology that is very similar to the prior artmanufacturing technology used to manufacture for example thin filmmagnetic heads or chips. For example a wafer substrate of suitable shapecould be provided, such as a glass substrate, on which a plurality ofthin-film in-plane magnetic coils 3 may be deposited using suitablestepper replication techniques to produce a plurality of individualthin-film in-plane magnetic coils 3 each disposed on a correspondingcoil substrate 7 provided in the wafer substrate.

An auxiliary substrate having dimensions in accordance with the wafersubstrate could be disposed over the wafer substrate and over thethin-film in-plane magnetic coils. Subsequently, in a first dicing step,the wafer substrate may be diced in a first direction into individualwafer substrate strips comprising rows of coil substrates havingthin-film in-plane magnetic coils deposited thereon while leaving theauxiliary substrate intact. In a second dicing step the auxiliarysubstrate and the said individual wafer substrate parts disposedthereover may be diced in a second direction different from the firstdirection into strip shaped auxiliary substrates 33 each supporting aplurality of diced individual wafer substrate parts comprising a coilsubstrate 7 and a thin-film in-plane magnetic coil 3 deposited thereon,the coil lead in and lead out sections 11,15 of each individual magneticcoil being formed such and the dicing steps being executed such thatafter the second dicing step a cross section of the lead in and lead outsections 11,15 is exposed at an edge of the interconnecting part 9A of aside surface 9 of the coil substrates 7.

In FIGS. 7 to 9 the strip shaped auxiliary substrates 33 show shallowgrooves 65 which are present between the individual coil substrates 7and which remain after the first dicing operation.

The manufacturing method which has been discussed with reference toFIGS. 7, 8 and 9 comprises the interesting feature that the coil lead insection 11 and the coil lead out section 15 are exposed at the edge ofthe interconnection part 9A of the side surface 9 after the seconddicing operation. Providing the interconnecting conductors 21 and 23 onthe side surface 9A of the coil substrate 7, which side surface 9A isflush with the side surface 37 of the auxiliary substrate 33, thereforeautomatically provides an electrical connection between the coil lead insection and coil lead out section and the first and secondinterconnecting conductors 21, 23 respectively.

Although the invention has been described in relation to a limitednumber of embodiments of the invention, it should be appreciated thatthe invention is by no means limited to the embodiments described butinstead is limited only by the scope of the independent claims 1, 2, 8and 9. Interesting embodiments are described in the respective dependingclaims.

REFERENCES

-   [1] Japanese Journal of Applied Physics, Vol. 40 (2001), pp.    1775-1777, Part 1, No. 3B, March 2001-   [2] European Patent Application Filing No. 00201412.4 (=PHNL000221)-   [3] European Patent Application Filing No. 01200477.6 (=PHNL 010093)

1. Method of manufacturing a magneto-optical write and/or read head (1)including a thin-film in-plane magnetic coil (3) disposed on anoutwardly directed surface (5A) of a coil substrate (7), the methodcomprising the steps of: providing an electrically isolating coilsubstrate (7) having substantially parallel main surfaces (5A, 5B)comprising the outwardly directed surface (5A) and an opposed topsurface (5B), interconnected by an adjoining side surface (9),depositing a thin film magnetic coil (3) on the outwardly directedsurface (5A) of the coil substrate (7) comprising a continuouselectrical conductor pattern with a coil lead in section (11), a coilwinding section (13) and a coil lead out section (15) and providingmeans for contacting the thin film magnetic coil (3) by electricallyconnecting the coil lead in and lead out sections (13,15) to externallead in and lead out lines (25,27), characterized in that the methodcomprises a plurality of further manufacturing steps including:extending the coil lead in and coil lead out sections (11,15) of themagnetic coil (3) on the outwardly directed surface (5A) of the coilsubstrate (7) to an interconnection part (9A) of the side surface (9) ofthe coil substrate (7), and depositing a pattern of respective first andsecond spaced interconnecting conductors (21,23) on the interconnectionpart (9A) of the side surface (9) of the coil substrate (7) inelectrical connection with the lead in and lead out sections (11,15)respectively of the magnetic coil (3) for contacting the said externallead in and lead out lines (25,29) respectively by suitable contactingmeans such as bonding, welding or soldering, such that a lead inconductor is formed comprising the first interconnecting conductor (21)and the lead in section (11) of the magnetic coil respectively and alead out conductor is formed comprising the second interconnectingconductor (23) and the lead out section (15,19) of the magnetic coil,respectively.
 2. Method of manufacturing a digital magneto-optical writeand/or read head (1) including a thin-film in-plane magnetic coil (3)disposed on an outwardly directed surface (5A) of a coil substrate (7),the method comprising the steps of: providing an electrically isolatingsubstrate (7) having substantially parallel main surfaces (5A, 5B)comprising the outwardly directed surface (5A) and an opposed topsurface (5B), interconnected by an adjoining side surface (9),depositing a thin film magnetic coil (3) on the outwardly directedsurface (5A) of the coil substrate (7) comprising a continuouselectrical conductor pattern with a coil lead in section (11), a coilwinding section (13) and a coil lead out section (15), and providingmeans for contacting the thin film magnetic coil (3) by electricallyconnecting the coil lead in and lead out sections (11,15) to externallead in and lead out lines (25,27), characterized in that the methodcomprises a plurality of further manufacturing steps including:extending the coil lead in and coil lead out sections (11,15) of themagnetic coil (3) on the outwardly directed surface (9A) of the coilsubstrate (7) to an interconnection part (9A) of the side surface (9) ofthe coil substrate (7), depositing a pattern of respective first andsecond spaced interconnecting conductors (21,23) on the interconnectionpart (9A) of the side surface (9) of the coil substrate (7) inelectrical connection with the lead in and lead out sections (11,15) ofthe magnetic coil (3) respectively and depositing a pattern ofrespective spaced first and second contacting conductors (29,31) on acontacting part (5C) of the top surface (5B) of the coil substrate (7)in electrical connection with the first and second interconnectingconductors (21,23) respectively on the side surface (9A) of the coilsubstrate (7) for contacting the said external lead in and lead outlines (25,27) respectively by suitable contacting means such as bonding,welding or soldering, such that a lead in conductor is formed comprisingthe first contacting conductor (29), the first interconnecting conductor(21) and the lead in section (11) of the magnetic coil respectively anda lead out conductor is formed comprising the second contactingconductor (31), the second interconnecting conductor (23) and the leadout section (15) of the magnetic coil (3) respectively.
 3. Methodaccording to claim 1, characterized in that the method comprises aplurality of further manufacturing steps including: providing anauxiliary substrate (33) having a supporting surface (35) and anadjoining auxiliary side surface (37), after depositing the thin filmmagnetic coil (3) on the outwardly directed surface (5A) of the coilsubstrate (7) but prior to the steps of depositing the interconnectingconductors (21,23) on the interconnection part (9A) of the side surfaceof the coil substrate (35), detachably arranging the coil substrate (7)on the supporting surface (35) of the auxiliary substrate (33) in aposition such that the thin film magnetic coil (3) is directed to thesupporting surface (35) and the interconnection part (9A) of the sidesurface (9) of the coil substrate (7) is flush with the auxiliary sidesurface (37) of the auxiliary substrate (33), providing a mask (39) overat least a part of the interconnection part (9A) of the side surface (9)such that the areas for disposing the interconnecting conductors (21,23)remain exposed areas, depositing a layer of conducting material over atleast a part of the mask (39) and over the said exposed areas, removingthe mask (39) and any conducting material deposited thereon so that thepattern of spaced interconnecting conductors (21,23) remains on theinterconnecting part (9A) of the side surface (9) of the coil substrate(7), and detaching the coil substrate (7) from the auxiliary substrate(33).
 4. Method according to claim 2, characterized in that the methodcomprises a plurality of further manufacturing steps including:providing an auxiliary substrate (33) having a flat supporting surface(35) and an adjoining auxiliary side surface (37), after depositing thethin film magnetic coil (3) on the outwardly directed surface (5A) ofthe coil substrate (7) but prior to the steps of depositing theinterconnecting conductors (21,23) on the interconnection part (9A) ofthe side surface (9) of the coil substrate (7) and depositing thecontacting conductors (29,31) on the contacting part (5C) of the topsurface (5B) of the coil substrate (7), detachably arranging the coilsubstrate (7) on the supporting surface (35) of the auxiliary substrate(33) in a position such that the thin film magnetic coil (3) is directedto the supporting surface (35) and the interconnection part (9A) of theside surface (9) of the coil substrate (7) is flush with the auxiliaryside surface (37) of the auxiliary substrate (33), providing a mask (39)over at least a part of the interconnection part (9A) of the sidesurface (9) and a part of the top surface (5B) of the coil substrate (7)such that the areas for disposing the interconnecting conductors (29,31)and contacting conductors (29,31) remain exposed areas, depositing alayer of conducting material over at least a part of the mask (39) andover the said exposed areas, removing the mask (39) and any conductingmaterial deposited thereon so that the pattern of spaced interconnectingconductors (21,23) and contacting conductors (29,31) remains on theinterconnecting part (9A) of the side surface (9) and the contactingpart (5C) of the top surface (5B) respectively of the coil substrate (7)and detaching the coil substrate (7) from the auxiliary substrate (33).5. Method according to claim 3 or 4, characterized in that the coilsubstrate (7) is detachably arranged on the supporting surface (35) ofthe auxiliary substrate (33) by adhesive means disposed between theoutwardly directed surface (5A) of the coil substrate (7) and thesupporting surface (35) of the auxiliary substrate (33).
 6. Methodaccording to claim 3, 4 or 5, characterized in that the method comprisesa plurality of further manufacturing steps including: providing a wafersubstrate, depositing a plurality of thin-film in-plane magnetic coils(3) on the wafer substrate using suitable stepper replication techniquesto produce a plurality of individual thin-film in-plane magnetic coils(3) each disposed on a corresponding coil substrate (7) provided in thewafer substrate, disposing an auxiliary substrate (33) over the wafersubstrate, in a first dicing step dicing the wafer substrate in a firstdirection into individual wafer substrate strips comprising rows of coilsubstrates (7) having thin-film in-plane magnetic coils (3) depositedthereon while leaving the auxiliary substrate intact, and in a seconddicing step dicing the auxiliary substrate and the said individual wafersubstrate strips disposed thereover in a second direction different fromthe first direction into strip shaped auxiliary substrates (33) eachsupporting a plurality of diced individual wafer substrate partscomprising a coil substrate (7) and a thin-film in-plane magnetic coil(3) deposited thereon, the coil lead in and lead out sections (11,15) ofeach individual magnetic coil (3) being formed such and the dicing stepsbeing executed such that after the second dicing step a cross section ofthe lead in and lead out sections (11,15) is exposed at an edge of theinterconnecting part (9A) of a side surface (9) of the coil substrate(7).
 7. Method according to claim 2 or 4, characterized in that the coilsubstrate (7) is transparent, an optical lens part (41) of an opticalpick up is provided on the top surface (5B) of the coil substrate (7) ina position between the position of the lead in and lead out conductors(29,21,11;31,23,15), such that any light focussed through the lens part(41) passes through the finished coil substrate (7) unobstructed by thelead in and lead out conductors (29,21,11;31,23,15).
 8. Magneto-opticalwrite and/or read head having a thin-film in-plane magnetic coil (3)disposed on an outwardly directed surface (5A) of the head, comprising:an electrically isolating coil substrate (7) having substantiallyparallel main surfaces (5A, 5B) comprising the outwardly directedsurface (5A) and an opposed top surface (5B), interconnected by anadjoining side surface (9), a thin film magnetic coil (3) deposited onthe outwardly directed surface (5A) of the coil substrate (7) comprisinga continuous electrical conductor pattern with a coil lead in section(11), a coil winding section (13) and a coil lead out section (15), andmeans for contacting the thin film magnetic coil (3) by electricallyconnecting the coil lead in and lead out sections (11,15) to externallead in and lead out lines (25,27), characterized in that the headcomprises: extended coil lead in and coil lead out sections (11,15) ofthe magnetic coil (3) on the outwardly directed surface (5A) extendingto an interconnection part (9A) of the side surface (9) of the coilsubstrate (7), and a pattern of respective first and second spacedinterconnecting conductors (21,23) deposited on the interconnection part(9A) of the side surface (9) of the coil substrate (7) in electricalconnection with the lead in and lead out sections (11,15) respectivelyof the magnetic coil (3) for contacting the said external lead in andlead out lines (25,27) respectively by suitable contacting means such asbonding, welding or soldering, such that a lead in conductor is formedcomprising the first interconnecting conductor (21) and the lead insection (11) of the magnetic coil (3) respectively and a lead outconductor is formed comprising the second interconnecting conductor (23)and the lead out section (15) of the magnetic coil respectively. 9.Magneto-optical write and/or read head having a thin-film in-planemagnetic coil (3) disposed on an outwardly directed surface (5A) of thehead, comprising: an electrically isolating coil substrate (7) havingsubstantially parallel main surfaces (5A,5B) comprising the outwardlydirected surface (5A) and an opposed top surface (5B), interconnected byan adjoining side surface (9), a thin film magnetic coil (3) depositedon the outwardly directed surface (5A) of the coil substrate (7)comprising a continuous electrical conductor pattern with a coil lead insection (11), a coil winding section (13) and a coil lead out section(15) and means for contacting the thin film magnetic coil (3) byelectrically connecting the coil lead in and lead out sections (11,15)to external lead in and lead out lines (25,27), characterized in thatthe head comprises: extended coil lead in and coil lead out sections(11,15) of the magnetic coil (3) on the outwardly directed surface (5A)extending to an interconnection part (9A) of the side surface (9) of thecoil substrate (7), a pattern of respective first and second spacedinterconnecting conductors (21,23) deposited on the interconnection part(9A) of the side surface (9) of the coil substrate (7) in electricalconnection with the lead in and lead out sections (11,15) of themagnetic coil (3) respectively and a pattern of respective spaced firstand second contacting conductors (29,31) deposited on a contacting partof the top surface (5B) of the coil substrate (7) in electricalconnection with the first and second interconnecting conductors (21,23)respectively on the side surface (9) of the coil substrate (7) forcontacting the said external lead in and lead out lines (25,27)respectively by suitable contacting means such as bonding, welding orsoldering, such that a lead in conductor is formed comprising the firstcontacting conductor (29), the first interconnecting conductor (21) andthe lead in section (11) of the magnetic coil respectively and a leadout conductor is formed comprising the second contacting conductor (31),the second interconnecting conductor (23) and the lead out section (15)of the magnetic coil (3) respectively.
 10. Write/read head according toclaim 9, characterized in that the coil substrate (7) is transparent, anoptical lens part of an optical pick up is provided on the top surface(5B) of the coil substrate (7) in a position between the lead in andlead out conductors (29,21,11;31,23,15), such that any light focussedthrough the lens part passes through the coil substrate (7) unobstructedby the lead in and lead out conductors (29,21,11;31,23,15).